1. Technical Field
The present invention relates to an image forming apparatus, a network printing system, a power save control method, and a power save control program, and more particularly to an image forming apparatus, a network printing system, a power save control method, and a power save control program to conduct a power-saving operation efficiently while enhancing a power-saving effect.
2. Background Art
With the advent of office automation (OA), network printing systems can now be configured with one or more host apparatuses or terminal apparatuses such as personal computers and word processors, in which the one or more host apparatuses share a plurality of printers connected via the network.
In such a network printing system, when a plurality of host apparatuses use the connected printers, many print jobs are issued to the printers, and the printers process the issued print jobs sequentially.
With rising demand for reduced resource use, resource use reduction is also expected of image forming apparatuses. Accordingly, such image forming apparatuses are now equipped with a power-saving function, such that, if no operation request is issued in a stand-by mode for a given time period, the image forming apparatus is shifted to a power save mode in which power supply to major components is stopped, or the power supply is reduced for lower energy consumption.
However, in such a network printing system, the power-saving function is activated for each image forming apparatus independently, which means each image forming apparatus reduces power consumption independently. Therefore, the power consumption for the entire network printing system may not be reduced effectively.
Conventionally, an image forming apparatus connected to a plurality of client terminals via a network includes a setting unit to set the power save mode, and a storage unit to store print history of each one of the client terminals. The setting unit refers to the print history stored in the storage unit, and based on attributes of each of the client terminals, the setting unit determines whether or not to shift the image forming apparatus to the power save mode.
For example, JP-2010-003083-A discloses a technique in which shifting to the power save mode is conducted by referring to the print history of the client terminals and attributes of the client terminals. However, if a plurality of image forming apparatuses and a plurality of client apparatuses are connected on a network, such technology may not be effective for the entire network system.
In a network printing system configured with a plurality of image forming apparatuses and a plurality of host apparatuses connected one to another via a network, the plurality of image forming apparatuses can conduct the power save control using the above mentioned conventional method, which uses stored print histories of client apparatuses and attributes of each of client apparatuses to shift to the power save mode. Such power save control is conducted for each one of the image forming apparatuses independently without considering the entire network printing system. Therefore, a resource imbalance may occur between active image forming apparatuses and active client apparatuses in which the number of active image forming apparatuses may become excessive compared to the number of active client apparatuses, by which the power consumption for the entire network printing system cannot be reduced effectively.